In the past bone plates were available only in a limited variety. For a particular bone type, one or more generic bone plates were offered. Depending on the nature of, for example, a particular fracture, a surgeon had to manually customize the generic bone plate according to fracture-specific needs. Such customizations typically included bending operations to conform the plate to the shape of a bone and cutting operations to adjust a length of the plate.
Today, bone plates are not only offered for specific bone types, but also in various designs for individual types of bone fractures. Moreover, bone plates are also designed based on patient-specific data. In this regard U.S. Pat. No. 6,978,188 B1 discloses a method for contouring a bone reconstruction plate based on medical image data representative of a patient's anatomy. A reconstruction plate is generally employed for covering (e.g., bridging) a bone gap that resulted from removal of a bone portion. The bone gap may be filled with bone material taken from other bones of the patient, wherein the reconstruction plate takes the load of the removed bone portion while the added bone material integrates with the remaining bone.
The bone plate contouring approach of U.S. Pat. No. 6,978,188 B1 includes a three-dimensional surface reconstruction of the removed bone portion based on the medical image data. The three-dimensional surface reconstruction is used to create a representation of a template of the bone plate that is contoured to fit the patient's anatomy. In a last step, the template is manufactured using a rapid prototyping process. The resulting template with its customized contour can be used for implantation or for pre-contouring an implantable plate prior to surgery.
Another computer-implemented technique for designing an implant such as a bone plate is known from US 2009/0149977 A1 (now abandoned). The technique comprises visualizing patient-specific data to permit a surgeon to manipulate a virtual model of the patient's anatomy, the implant, or both, until the implant is ideally positioned within the virtual model. For designing, modifying or manipulating a virtual image of the implant, an interaction with the virtual model of the anatomy takes place. Specifically, the virtual model of the anatomy is altered in a first step. In a second step a standard bone plate is selected from a list of virtual plates and placed in the desired position on the altered virtual model. Then, the selected standard bone plate is automatically adapted to fit an amount of bone displacement and surface contours of the altered virtual model.
It has been found that the plate design approaches suggested in U.S. Pat. No. 6,978,188 B1 and US 2009/0149977 A1 do in many cases still require substantial customization operations by the surgeon in the operating room. It has further been found that this drawback can at least in part be attributed to the fact that the design of the bone plate is to a large extent based on predefined standard bone plates.